This bash script checks if there are any new plugins added to the Mattermost plugin marketplace, and creates a new post through a Mattermost incoming webhook request. See the comment below for more details.

scrape_new_plugins.sh

#!/usr/bin/env bash

if [ -z "$MM_WEBHOOK_URL" ]
then
  echo "Please set the MM_WEBHOOK_URL environment variable"
  exit 0
fi

LOCAL_PLUGINSJSON_PATH="plugins.json"
REMOTE_PLUGINSJSON_PATH="new_plugins.json"

REMOTE_URL=https://raw.githubusercontent.com/mattermost/mattermost-marketplace/production/plugins.json
echo ""
echo "Fetching remote plugins from $REMOTE_URL"
echo ""

curl $REMOTE_URL -o $REMOTE_PLUGINSJSON_PATH --silent

if [ ! -f $LOCAL_PLUGINSJSON_PATH ]; then
  cp $REMOTE_PLUGINSJSON_PATH $LOCAL_PLUGINSJSON_PATH
  echo "Saved remote marketplace entries to plugin.json"
  echo "First time running program"
  echo "Exiting with nothing to compare"
  exit 0
fi

local_keys=$(jq -r '.[] | .manifest.id + "|" + .manifest.version' $LOCAL_PLUGINSJSON_PATH)
remote_keys=$(jq -r '.[] | .manifest.id + "|" + .manifest.version' $REMOTE_PLUGINSJSON_PATH)

# Backup plugins.json file
mv $LOCAL_PLUGINSJSON_PATH ${LOCAL_PLUGINSJSON_PATH}.bak
mv $REMOTE_PLUGINSJSON_PATH $LOCAL_PLUGINSJSON_PATH

local_array=($local_keys)
remote_array=($remote_keys)

HAS_NEW_PLUGINS=0
for rkey in "${remote_array[@]}"; do
    FOUND_EXISTING_ENTRY=0
    for lkey in "${local_array[@]}"; do
        if [ "$rkey" == "$lkey" ]; then
            FOUND_EXISTING_ENTRY=1
            break
        fi
    done
    if [ $FOUND_EXISTING_ENTRY -ne 1 ]; then
        if [ $HAS_NEW_PLUGINS -ne 1 ]; then
          echo "New plugins found:"
          HAS_NEW_PLUGINS=1
        fi

        # Split the key into id and version.
        ID="${rkey%|*}"
        VERSION="${rkey#*|}"
        echo "- $ID v$VERSION"

        # Extract the full object that matches the id and version
        JSON=$(jq --arg id "$ID" --arg version "$VERSION" \
            '.[] | select(.manifest.id == $id and .manifest.version == $version)' $LOCAL_PLUGINSJSON_PATH)

        NAME=$(jq -r '.manifest.name' <<< "$JSON")
        VERSION=$(jq -r '.manifest.version' <<< "$JSON")
        MIN_SERVER_VERSION=$(jq -r '.manifest.min_server_version' <<< "$JSON")
        RELEASE_NOTES=$(jq -r '.release_notes_url' <<< "$JSON")

        # ...

        echo '{
          "username": "Plugin Marketplace",
          "icon_url": "https://mattermost.com/wp-content/uploads/2022/02/icon.png",
          "attachments":[{
            "fallback": "'$NAME $VERSION' was added to the Marketplace",
            "title": "'$NAME $VERSION' was added to the Marketplace",
            "text": "Release notes can be found [here]('$RELEASE_NOTES'). It requires Mattermost Server '$MIN_SERVER_VERSION'."
          }]
        }' > mattermost.json

        # Send webhook request to Mattermost
        curl -i -X POST -H 'Content-Type: application/json' -d @mattermost.json $MM_WEBHOOK_URL --silent --output /dev/null --show-error --fail
    fi
done

if [ $HAS_NEW_PLUGINS -ne 1 ]; then
  echo "No new plugins found when comparing remote marketplace to local copy"
fi

This bash script checks if there are any new plugins added to the Mattermost plugin marketplace, and creates a new post through a Mattermost incoming webhook request. The script downloads the latest listing, and compares that with a locally stored version of the listing. On the first run of the script, no post will be made since there is nothing to compare to.